The present invention relates to a pressure switch for moving a contact arrangement.
In known pressure switches of this kind the first spring arrangement is usually located in the longitudinal apparatus axis, while the second spring arrangement, which exerts its spring force only after play has been overcome, acts on the rocking lever near the free end of the latter. The first and second spring arrangements may also be transposed in position in the pressure switch. In all embodiments of the known pressure switches, the spring, situated in the longitudinal apparatus axis and having the form of a coil compression spring, is supported against a pull rod. In known pressure switches said rod is fastened to the switch frame mounting the contact carrier and the rocking lever. In addition, in known pressure switches the force produced by the drive unit and proportional to the fluid pressure is transmitted via the transmission member exclusively to the rocking lever, which distributes the force between the two spring arrangements. In known pressure switches the rocking lever and also the switch frame thus exposed to considerable forces, which on the one hand require an expensive sturdy construction and on the other hand reduce switching accuracy. These difficulties occur to an even greater extent if the pressure switch is required to master a great switching difference, that is to say if, for example, its contact arrangement goes into the OFF position at a pressure of 100 bar and into the ON position at a pressure of for example 20 bar.